1. Technical Field
This invention relates to displays, and more particularly to, a simplified assembly of a liquid crystal display that has an improved ground plane.
2. Related Art
In general, liquid crystal display modules include a liquid crystal display panel having liquid crystal cells positioned between two substrates. An illuminating unit may be placed behind the liquid crystal display panel to improve clarity and brighten the display panel. Optical sheets may be placed between the illuminating unit and the liquid crystal display to collect and concentrate light against the display to achieve an even greater brightness. To minimize light losses, the optical sheets may form an integral part of the liquid crystal display.
FIG. 1 and FIG. 2 illustrate a liquid crystal display module that includes a liquid crystal display panel 6, an inner support 24, and a case 2. The case 2 encloses a portion of the inner support 24 and the liquid crystal display panel 6. An illuminating unit (not shown) having a plurality of lamps is positioned behind the liquid crystal display panel 6. A cover 14 disposed below a plurality of optical sheets receives the light that is spread across its surface.
In FIG. 1, the liquid crystal display 6 is comprised of an upper substrate 5 and a lower substrate 3 separated by a liquid crystal layer An array of liquid crystals (not shown) injected between the upper and the lower substrates 3 and 5 polarize the light passing through it.
In a matrix display, data lines, gate lines, and other components that are not shown may be formed on the lower substrate 3. A thin film transistor (TFT) in electrical contact with a data and a gate line form one of the many liquid crystal cells that make up the display. The TFT passes data signal to the liquid crystal cell when biased by a scanning pulse (e.g., a gate pulse).
In some matrix displays, a side surface of the lower substrate 3 has data and gate pads. Data circuits 8 mounted to a data drive integrated circuit 10 are electrically linked to the data lines through the data pads. Gate circuits 4 mounted to a gate drive integrated circuit 12 are electrically linked to the gate lines through the gate pads.
As shown in FIG. 2, the first and second circuit boards 20 and 22, and the gate circuit board 26 are positioned proximate to the support 24. In this display, the gate circuit board is secured to the bottom cover with tape and the first and second data circuit boards 20 and 22 are secured to the bottom cover 14 by threaded screws 30 and 32 (See FIG. 3). The screws 30 and 32 pass through first and second holes 34 and 36 of the first and second circuit boards 20 and 22, respectively, before passing through fastening holes formed in the bottom cover 14. The threaded screws 30 and 32 and bottom cover act as a ground plane for the first, second, and gate circuit boards 20, 22, and 26.
Since the ground plane act as a reference for the voltages in circuit, a weak or intermittent ground may affect the display's performance. If one or more screws 30 and 32 fall out of engagement with the bottom cover 14, the conducting path to ground decreases which may lead to display failure and a loose inner assembly. Moreover in some displays, the multiple screws must first be properly aligned before being evenly and progressively tightened to minimize circuit and board stress in the assembly process. This practice may complicate the assembly process and increases assembly time. The present inventions are directed to an improved display that overcomes some of these potential drawbacks of the related art.